‘Yet again we're looking for deficiency in a young person's ambition when the actual barriers are functional and economic.' Illustration by Matt Kenyon

The oath sworn by the Guides has been an open sore in my psyche since 1981, when my mum wouldn't let me join because of the promise to serve God, Queen and country. Asked which of the three allegiances she objected to, she replied that she really couldn't be forced to choose between organised religion, the royal family and mindless patriotism, despising them all equally. Then, 32 years later, they finally change the oath to reflect the nation's changing spiritual landscape; only now I object to it, and won't be letting my daughter join either. This is what they call a hard-to-reach cycle of leftiness. It won't be broken until some agency is put in charge of our rehabilitation and paid by results.

The oath now reads: "I promise that I will do my best: to be true to myself and develop my beliefs, to serve the Queen and my community, to help other people and to keep the (Brownie) Guide law." (They have to put "Brownie" in brackets since the meaning of the word has changed so much.) A statement from the organisation said, "Guiding believes in having one promise that is a clear statement of our core values", although the keen observer will notice that the oath contains seven promises. If I were to change it again, it would say "develop my maths" and then "develop my beliefs".

This schmaltzy formulation of "truth to oneself" crops up regularly in the basket of helpful things to bestow on adolescents. It's a strange instruction to a person of any age, relying on the idea that you have this irreducible core, this righteous quiddity, and if you make sure it isn't compromised you'll leave the Earth having done more good than harm. In truth, I think its real meaning is "don't be an arse", and that is a helpful though underused edict for life. But to be "true to oneself" sounds loftier.

In the context of a 12-year-old, it is even more ridiculous than it is for an adult, who may at least reflexively decode it. What is that "self"? How is it distinguishable from one's parents' sense of self? How does one establish oneself as a person distinct from the family if not by testing ideas and identities and personas that, on the face of it, are pretty unlike oneself, or are certainly unlike one's 10-year-old self? Isn't adolescence by definition a state of flux?

This message holds no meaningful or useful clues for a young person; instead, it ascribes to them something they couldn't possibly have, and creates, or bolsters, what is identified in Richard Wilkinson and Kate Pickett's book, The Spirit Level, as "threatened egotism", or "unhealthy self-esteem" or "insecure narcissism". The authors discussed a study in which teenagers were asked to agree or disagree with the statement, "I am a very important person". In the 1950s, 12% agreed. In the 1980s, 80% did. This wasn't accompanied by less anxiety or depression, by better outcomes, or by better prospects. The solid, important self had been asserted without its perimeters or resilience ever being tested. This can have a fake-it-till-you-make-it effect, but more often people whose esteem rests heavily on denying weakness feel weakened by this undefended flank called reality.

So long as young people are prepared to make bold statements about their core beliefs and aspirations, there is held to be no need for those beliefs to challenge the status quo, or those aspirations to stand a realistic chance of success. The Joseph Rowntree Foundation has undertaken this research more than once. (Frustrated, most likely, that not enough people listened in 2010, they produced another report in 2012.) There is no aspiration gap; at 14 (in the first study), children from poor backgrounds had the same hopes of higher education as children from rich backgrounds. If you want to know why those 14-year-olds didn't end up at Russell Group universities four years later, it's a straight results gap; increasingly, a money gap; and, less demonstrably but quite probably, an aspiration gap on the part of the admissions tutors.

And yet it continues, with culture secretary Maria Miller announcing this month an "information pack" for the parents of daughters on how to make sure aspiration is fostered at home. Its rationale is that women fail in the world of work, and that if women were as entrepreneurial as men, there would be a million more entrepreneurs. Work is a natural focal point, since girls are already outperforming boys at school and university – although of course there will be churlish feminists asking, "Where's the information pack for the parents of boys, teaching them how to aspire not to be outperformed by girls throughout their schooling?"

But that's not what bothers me; what bothers me is that, yet again, we're looking for the deficiency in some young person's ambition when the actual barriers are entirely economic and functional – viz, if you want women to work like men, you have to free them from the childrearing, and that is something society can only do together (even if we did manage to co-operate for five seconds to sort that out, not all women would see it as freedom).

In short, it is asking of young people an absurd amount, that they maintain some sense of themselves distinct from the society they live in, never mind that they should aspire their way out of the structures that make some people's dreams a lot more realistic than others'. The Guides, whose founding pillars actually are quite useful – a pride in community, coupled to an altruism that is active, collective and strong, not servile – should know better than to proselytise a babyish truism that is actively untrue.